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Synthesis, tautomeric forms, specific intermolecular interactions, and lipophilicity of methylated 6-hydroxypyridazine-3-carboxylic acid and its 4,5-dihydro analogs
- Source :
-
Journal of Molecular Structure . Jul2011, Vol. 998 Issue 1-3, p84-90. 7p. - Publication Year :
- 2011
-
Abstract
- Abstract: Effects of methylation for intermolecular interactions and lipophilicity have been studied for a series of methylated 4,5-dihydro-6-hydroxypyridazine-3-carboxylic and 6-hydroxypyridazine-3-carboxylic acids (1 and 2). In solution they exist in equilibrium of the lactam and lactim tautomers, with the reverse preferences for analogs 1 and 2, which affect the syntheses of their methylated derivatives. Carboxylic acid 2 preferably crystallizes as a hydrate, built of carboxylate anions and hydronium cations 2 − H3O+, hydrogen bonded into catemeric patterns involving both ions. In methyl 4,5-dihydro-6-oxopyridazine-3-carboxylate (4A) the molecules are NH⋯O hydrogen bonded into chains. In both structures 2 − H3O+ and 4A, there are relatively strong CH⋯O hydrogen bonds, arranging the molecules into sheets. The increased lipophilicity of the methylated derivatives has been correlated with the formation of CH⋯O bonds. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 00222860
- Volume :
- 998
- Issue :
- 1-3
- Database :
- Academic Search Index
- Journal :
- Journal of Molecular Structure
- Publication Type :
- Academic Journal
- Accession number :
- 61922122
- Full Text :
- https://doi.org/10.1016/j.molstruc.2011.05.016